Which of the following does NOT include a component of blood vessels?

The choice identifying alveoli as not including a component of blood vessels is accurate because alveoli are the tiny air sacs in the lungs where gas exchange occurs. They are part of the respiratory system, not the cardiovascular system. In contrast, arteries, capillaries, and veins are all integral components of the blood vessel network.

Arteries carry oxygen-rich blood away from the heart; capillaries facilitate the exchange of gases, nutrients, and waste between blood and tissues; and veins return deoxygenated blood back to the heart. Therefore, the distinction between alveoli and the blood vessels is fundamental in understanding their roles in respiration versus circulation.